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| author |   Sean Christopherson <seanjc@google.com> | 2022-08-30 23:15:54 +0000 |
|---|---|---|
| committer |   Paolo Bonzini <pbonzini@redhat.com> | 2022-09-26 12:03:05 -0400 |
| commit | b9d44f9091ac6c325fc2f7b7671b462fb36abbed (patch) | |
| tree | 082c475bec4d25379e899bef8b5ea55b27cf394a /arch/x86/kvm/vmx/nested.c | |
| parent | KVM: nVMX: Treat General Detect #DB (DR7.GD=1) as fault-like (diff) | |
| download | linux-dev-b9d44f9091ac6c325fc2f7b7671b462fb36abbed.tar.xz linux-dev-b9d44f9091ac6c325fc2f7b7671b462fb36abbed.zip | |
KVM: nVMX: Prioritize TSS T-flag #DBs over Monitor Trap Flag
Service TSS T-flag #DBs prior to pending MTFs, as such #DBs are higher
priority than MTF. KVM itself doesn't emulate TSS #DBs, and any such
exceptions injected from L1 will be handled by hardware (or morphed to
a fault-like exception if injection fails), but theoretically userspace
could pend a TSS T-flag #DB in conjunction with a pending MTF.
Note, there's no known use case this fixes, it's purely to be technically
correct with respect to Intel's SDM.
Cc: Oliver Upton <oupton@google.com>
Cc: Peter Shier <pshier@google.com>
Fixes: 5ef8acbdd687 ("KVM: nVMX: Emulate MTF when performing instruction emulation")
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Link: https://lore.kernel.org/r/20220830231614.3580124-8-seanjc@google.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/vmx/nested.c')
| -rw-r--r-- | arch/x86/kvm/vmx/nested.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index 9e25e759b486..60e6a261c723 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -3985,15 +3985,17 @@ static int vmx_check_nested_events(struct kvm_vcpu *vcpu) } /* - * Process any exceptions that are not debug traps before MTF. + * Process exceptions that are higher priority than Monitor Trap Flag: + * fault-like exceptions, TSS T flag #DB (not emulated by KVM, but + * could theoretically come in from userspace), and ICEBP (INT1). * * Note that only a pending nested run can block a pending exception. * Otherwise an injected NMI/interrupt should either be * lost or delivered to the nested hypervisor in the IDT_VECTORING_INFO, * while delivering the pending exception. */ - - if (vcpu->arch.exception.pending && !vmx_get_pending_dbg_trap(vcpu)) { + if (vcpu->arch.exception.pending && + !(vmx_get_pending_dbg_trap(vcpu) & ~DR6_BT)) { if (vmx->nested.nested_run_pending) return -EBUSY; if (!nested_vmx_check_exception(vcpu, &exit_qual)) |